Mark Mattison-Shupnick, ABOM
Wondering what ANSI tolerances apply to compensated (optimized free-form) lenses? From a discussion at the Lens Technical Committee meeting of The Vision Council, tolerances are applied to the compensated lens power, not the doctor’s written prescription that was ordered.
Remember, the compensated lens power makes the effective power of the lens equal to the written prescription in the way that the lenses are positioned in front of the eyes considering vertex, tilt and wrap angles. Therefore, using the lab invoice, find the compensated lens power and when checking in lenses, apply the latest of ANSI Z80.1 – 2015 to those numbers. For
a summary of tolerances from The Vision Council, see thevisioncouncil.org.
To know more about standards, read the April 2017 20/20 article “Do Eyewear Standards Still Matter?” written by Barry Santini, ABOM.
May 2017
Lenses